James "Big Jim" Colosimo (born Giacomo Colosimo) (February 16, 1878 – May 11, 1920), also known as "Diamond Jim" was an Italian-AmericanMafiacrime boss who built a criminal empire in Chicago based on prostitution, gambling, and racketeering. Immigrating from Calabria, Italy in 1895, he gained power through petty crime and by heading of a chain of brothels. From about 1902 until his murder in 1920, he would lead a gang that would become known after his death as the Chicago Outfit. Johnny Torrio, an enforcer Colosimo imported in 1909 from New York, seized control after his death. Al Capone, a Torrio henchman, allegedly was directly involved in the murder.[1]

Later, Colosimo acquired another nickname, "Diamond Jim," because he frequently dressed in a white suit and wore diamond pins, rings, and other jewelry. This, combined with his personal charm and money, helped him establish relationships with women. He had a love of both women and money, which fueled his enthusiasm for prostitution. In 1902, Colosimo married Victoria Moresco, an established Chicago madame, and together they opened a second brothel. Within a few years, Colosimo had expanded this to nearly 200 brothels and had also made inroads into gambling and racketeering.[2]

By 1909, Black Hand extortion was a serious threat to Colosimo in Chicago. He brought in gangster John "The Fox" Torrio from Brooklyn and made him his second in command. The following year, he opened Colosimo's Cafe, a restaurant and nightclub at 2126 South Wabash. It quickly became a popular destination for prominent Chicagoans and visitors to Chicago. In 1919, Torrio and Colosimo opened a brothel at 2222 South Wabash called the Four Deuces, a reference to the address. Torrio hired his old Brooklyn colleague Al Capone to work as a bartender and bouncer, which gave Capone his entry into Chicago crime.[2]

When prohibition went into effect in 1920, Torrio pushed for the gang to enter into bootlegging, but Colosimo stubbornly refused. In May 1920, Colosimo left Chicago to marry his second wife, Dale Winter, having deserted Victoria Moresco. When he returned a week later, Torrio called and told him a shipment was about to arrive at his cafe. Colosimo drove there to await it, but instead he was shot from ambush and killed.[3] The initial suspect was his new wife Dale, but the murder officially went unsolved and no one was ever arrested or charged for it. Many believe that Torrio had ordered the killing so that he could go into the lucrative business of bootlegging. Torrio allegedly brought in a New York colleague, Frankie Yale, to eliminate Colosimo. Al Capone has also been suggested as the gunman.[2]

Colosimo was the first gang leader to organize the disparate parts of Chicago's crime scene. After his death, John Torrio took over his gang, later to be replaced by Al Capone. His mob eventually became the infamous Chicago Outfit that ruled over some parts of the city.[2]

In the 1932 gangster movie Scarface: The Shame of a Nation, the death of "Big Louie" Costillo is loosely based on Colsimo's assassination. Big Louie is killed by the main characters Johnny Lovo and Antonio Camonte. Lovo was based on Johnny Torrio and Camonte on Al Capone, with Costillo's murder to allow then to begin bootlegging.

In 2010, Colosimo's murder was depicted in the series premiere of HBO's Boardwalk Empire. It depicts Colosimo, played by Frank Crudele as the victim of a hit ordered by Torrio and committed by Frankie Yale to allow Torrio's gang to go into bootlegging.